Event processing system paging

Abstract

A pageable query can be generated based on an event-processing query. The pageable query is a form of the event-processing query that supports swapping the event-processing query into and out of memory. For instance, page-in and page-out triggers can be inserted. After detection of a page-in trigger, the event-processing query can be loaded into the memory, and after detection of a page-out trigger, the event-processing query can be unloaded from memory.

What is claimed is: 
     
       1. A system comprising:
 a processor coupled to a memory, the processor configured to execute computer-executable instructions stored in the memory that when executed perform acts comprising: 
 receiving an event-processing query, as part of a subscription, for continuous evaluation until the subscription is canceled; and 
 rewriting the event-processing query automatically in a pageable form, wherein the pageable form enables swapping of at least a portion of the event-processing query into and out of memory based on one or more injected triggers specified in terms of at least one characteristic of one or more of the event-processing query or an event sequence over which the event-processing query operates. 
 
     
     
       2. The system of  claim 1  further comprises injecting a page-in trigger into the pageable form that initiates loading of the at least the portion of the event-processing query into the memory. 
     
     
       3. The system of  claim 2 , the page-in trigger is generated based on historical data related to execution of the event-processing query. 
     
     
       4. The system of  claim 1  further comprises injecting a page-out trigger into the pageable form that initiates removal of the at least the portion of the event-processing query from the memory. 
     
     
       5. The system of  claim 4 , the page-out trigger is generated based on historical data related to execution of the event-processing query. 
     
     
       6. The system of  claim 1  further comprises gathering data regarding execution of the event-processing query. 
     
     
       7. A method comprising:
 employing at least one processor configured to execute computer-executable instructions stored in a memory to perform the following acts: 
 receiving an event-processing query, as part of a subscription, for continuous evaluation until the subscription is canceled; and 
 generating a pageable query automatically based on the event-processing query, wherein the pageable query supports swapping of at least a portion of the event-processing query into and out of the memory based on at least one characteristic of one or more of the event-processing query or an event sequence over which the event-processing query operates. 
 
     
     
       8. The method of  claim 7  further comprises injecting a page-in trigger into the pageable query that initiates loading of the at least the portion of the event-processing query into the memory. 
     
     
       9. The method of  claim 7  further comprises injecting a page-out trigger into the pageable query that initiates removing the at least the portion of the event-processing query from the memory. 
     
     
       10. The method of  claim 7  further comprises inserting a mechanism to defer loading of the at least the portion of the event-processing query into memory until triggered. 
     
     
       11. The method of  claim 7  further comprises inserting a mechanism to collect data related to execution of the event-processing query. 
     
     
       12. The method of  claim 11  further comprises employing machine learning with respect to the data to infer at least one of a page-in trigger or page-out trigger. 
     
     
       13. The method of  claim 7  further comprises inserting a mechanism to save state of the at least the portion of the event-processing query in connection with swapping the event-processing query out of the memory. 
     
     
       14. The method of  claim 7  further comprises inserting a mechanism to recover state of the at least the portion of the event-processing query in connection with swapping the event-processing query into the memory. 
     
     
       15. The method of  claim 7  further comprises inserting a mechanism to swap out of the memory a subset of the at least the portion of the event-processing query. 
     
     
       16. A computer-readable storage medium having instructions stored thereon that enable at least one processor to perform a method upon execution of the instructions, the method comprising:
 detecting a page-in trigger of an event-processing query specified in a pageable form that enables swapping of at least a portion of the event-processing query into and out of memory, wherein the page-in trigger is based on at least one characteristic of one or more of the event-processing query or an event sequence over which the event-processing query operates; and 
 loading at least a portion of an event-processing query located outside of memory into the memory in response to detecting the page-in trigger. 
 
     
     
       17. The computer-readable storage medium of  claim 16 , the method of loading the event-processing query comprises:
 locating a data representation of the at least the portion of the event-processing query based on an identifier; and 
 compiling the data representation to executable code. 
 
     
     
       18. The computer-readable storage medium of  claim 16 , the method further comprises:
 detecting a page-out trigger with respect to the event sequence; and 
 unloading the at least the portion of the event-processing query from memory in response to detecting the page-out trigger. 
 
     
     
       19. The computer-readable storage medium of  claim 18 , the method of unloading the event-processing query comprises initiating a state capture operation that captures current state of the event-processing query. 
     
     
       20. The computer-readable storage medium of  claim 18 , the method of unloading the event-processing query comprises unloading solely a subset of the at least the portion of the event-processing query.